feat(selection): expose run sector aggregates and sector filter on results API

- sector_radar: add batch sector-count aggregation and sector member lookup
  over the strict last-good membership snapshot (postgres + in-memory fakes)
- selection: add SelectionSectorReader port, list_sector_counts use case,
  and sector_stock_codes filtering via run identity resolution; queries stay
  inside the selection context per ADR 0001
- http: add GET /api/v1/selection/sectors and forward sector param on
  /results and /runs/{run_id}
- fix stale positional args in pattern-scoring run tests; cover new behavior
  with read-service, application, and HTTP contract tests

zhixing-server/tests/test_selection_http.py

@@ -15,7 +15,10 @@ from zhixing_server.modules.selection.application.chart import (
     SelectionChartNotFound,
     SelectionChartPoint,
 )
-from zhixing_server.modules.selection.application.run import PreparedSelectionRun
+from zhixing_server.modules.selection.application.run import (
+    PreparedSelectionRun,
+    SelectionSectorAggregates,
+)
 from zhixing_server.modules.selection.domain.models import SelectionSignal, ZhixingB1Category
 from zhixing_server.modules.selection.domain.pattern_scoring import (
     PATTERN_SCORING_VERSION,
@@ -30,6 +33,7 @@ from zhixing_server.modules.selection.domain.runs import (
     SelectionResultQuery,
     SelectionRun,
     SelectionRunInProgress,
+    SelectionSectorCount,
     SelectionStock,
 )
 from zhixing_server.modules.selection.infrastructure.postgres_reader import (
@@ -45,11 +49,17 @@ TARGET = date(2026, 8, 8)
 
 
 class FakeSelectionService:
-    def __init__(self, run: SelectionRun | None = None) -> None:
+    def __init__(
+        self,
+        run: SelectionRun | None = None,
+        sectors: tuple[SelectionSectorCount, ...] = (),
+    ) -> None:
         self.run = run
+        self.sectors = sectors
         self.executed = False
         self.mode = "ok"
         self.last_query: SelectionResultQuery | None = None
+        self.sector_type_requested: str | None = None
 
     def prepare(
         self,
@@ -103,6 +113,23 @@ class FakeSelectionService:
             return None
         return self.run
 
+    def list_sector_counts(
+        self,
+        strategy: str,
+        target_trade_date: date | None = None,
+        *,
+        sector_type: str = "concept",
+    ) -> SelectionSectorAggregates | None:
+        self.sector_type_requested = sector_type
+        if self.run is None:
+            return None
+        return SelectionSectorAggregates(
+            run=self.run,
+            snapshot_trade_date=self.run.target_trade_date,
+            sector_type=sector_type,
+            sectors=self.sectors,
+        )
+
 
 class FakeChartService:
     """Return or fail one deterministic chart response."""
@@ -434,6 +461,83 @@ def test_query_rejects_invalid_page_size() -> None:
     assert response.status_code == 422
 
 
+def test_query_forwards_sector_filter() -> None:
+    service = FakeSelectionService(_run("run-http", "success"))
+
+    response = _client(service).get(
+        "/api/v1/selection/results",
+        params={"strategy": "zhixing_b1", "sector": "  BK0475.DC  "},
+    )
+
+    assert response.status_code == 200
+    assert service.last_query is not None
+    assert service.last_query.sector == "BK0475.DC"
+
+
+def test_sectors_returns_aggregated_counts_desc() -> None:
+    run = _run("run-http", "success")
+    service = FakeSelectionService(
+        run,
+        sectors=(
+            SelectionSectorCount(sector_code="BK0001.DC", sector_name="机器人", stock_count=3),
+            SelectionSectorCount(sector_code="BK0003.DC", sector_name="数字经济", stock_count=2),
+        ),
+    )
+
+    response = _client(service).get("/api/v1/selection/sectors")
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "strategy": "zhixing_b1",
+        "target_trade_date": "2026-08-08",
+        "run_id": "run-http",
+        "status": "success",
+        "snapshot_trade_date": "2026-08-08",
+        "sector_type": "concept",
+        "sectors": [
+            {"sector_code": "BK0001.DC", "sector_name": "机器人", "stock_count": 3},
+            {"sector_code": "BK0003.DC", "sector_name": "数字经济", "stock_count": 2},
+        ],
+    }
+
+
+def test_sectors_forwards_sector_type() -> None:
+    service = FakeSelectionService(_run("run-http", "success"))
+
+    response = _client(service).get(
+        "/api/v1/selection/sectors",
+        params={"sector_type": "industry"},
+    )
+
+    assert response.status_code == 200
+    assert service.sector_type_requested == "industry"
+    assert response.json()["sector_type"] == "industry"
+
+
+def test_sectors_without_run_returns_no_data() -> None:
+    response = _client(FakeSelectionService()).get("/api/v1/selection/sectors")
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "strategy": "zhixing_b1",
+        "target_trade_date": None,
+        "run_id": None,
+        "status": "no_data",
+        "snapshot_trade_date": None,
+        "sector_type": "concept",
+        "sectors": [],
+    }
+
+
+def test_sectors_rejects_unknown_sector_type() -> None:
+    response = _client(FakeSelectionService()).get(
+        "/api/v1/selection/sectors",
+        params={"sector_type": "macro"},
+    )
+
+    assert response.status_code == 422
+
+
 def test_chart_returns_bounded_qfq_contract() -> None:
     chart_service = FakeChartService()